Display device



www@ sie Y xr@l Jgsoag@ y CRSS `RE FRNCE NOV. 17, 1942. R, 1' IKR|EBEL2,302,556

DISPLAY DEVICE Filed Nov. 27, 1940 mainder'of said` beam.

Patented Nav. 17,1942

DSPLAY DEVICE' f Richard T. Kriebel, Aubnrndale, Mass., signor toPolaroid Corporation, Dover, Del., am.

, ,tion of Delaware -appuemnm Nevemberzr, 1940,' sel-m No. 367,413 t sclaim. (ci. ss--soi l This invention relates to display devices, andmore particularly to display devices employing I P01arlzed light.

Itis a 'particular object of lthis invention to -provide a displaydevice by which the glare-'free nature of appropriatelyv polarizedlightmay be demonstrated conveniently and simply.

Another object is to provide such a display de` vice wherein a beam oflight is projected on to a reflecting surface at substantially thepolarizing angle, of incidence and means are provided for dividing saidbeam, for absorbing the`horizon= tally vibrating component of one of thedivided portions of said beam, and for distinguishing the area of saidsurface illuminated by said polarized portion from the Aarea illuminatedbythe re- Another object is ito provide such a display de- -v'ice ininexpensive, portable and easily assembled form. v

ed to engage slots I8 in the bottom edge offln i2.

Elements i8 represent tabs cut out and bent up from Aelement I and whichmay, for example, bear advertising legends` or other indicia.

Element represents a lamp positioned to project light downward atapproximately the polarizing angle of incidence on to the reectingsurface ofelement i0. Lamp 20 contains a conventional bulb 22 provided.with agshade 24. Mounted within'shade 24 ,is a frame 2'6 containing asheet of light-polarizing material 25.. As is shown Other objects andadvantages will in part appear and in part be pointed out in the courseof l the following description of one embodiment v'of the invention,which is given as a non-limiting example, in connection with thefollowing drawing,in which: Y Figure i is a view in perspective, partlybrokend by the drawing, element 25 is positioned to intercept about halfof the light emitted by lamp 2l,

the other half of said'light passing through the open portion 28 offrame'f Polarizing element 25 may comprise any suit- ;able'sheetpolarizing material such, for example. as one of those sold under the-tradename Polaroid. As is indicated by arrow ,it should'be sopositioned that its transmission axis is substantially parallel with theplane of incidence on elel 'ment Ill of the beam-emitted by lamp 20, andin away, of a complete display device'embodylngg a form of theinvention; and

Figure 2 isa similar view wherein the perspec ltiveisatana'ngl'e of-90tothat in Pig. 1.

When a relatively hat surface or object is illu'- mi'nated by a beam ofliht projected obliquely thereon, a person viewing said surface from a ntion approximately opposite the'source of said -f receives the sensationof glare, the glare increasing as the angle of -incidence of the beam oflight approachesthe polarizing angle of incidence.. The -display deviceof the present inthi's position it follows that `it will absorb thatcomponent of said beam which is vibrating parallel to the surfaceofelement il.

It is believed that .the operation of the above* display device will nowbe apparent from the drawing.A The beam of'light emitted by bulb 22 isinitially unpolarized, as is indicated by the 80 bundle of arrows 32.Beam Il, which passes through open portion 28 of frame 26, continues -insubstantially unpolarized condition, as indicated'by arrows 34, until itreaches the-surface of lelement Il. A large p'ortion of said-beam,

as however, is specularly reflected and polarized to vibrate lparallelto said surface, as is indicated by arrow Il, while the rest of the beamremains substantially unpolarized as is indicatedv by'arrows Il. Thepredominance of this specularly rcvention is designed particularly todemonstrate 40 ected, horizontally vibrating Component PrO- the fact*that such .glare may be prevented by 1 removing from the projected beamthe component vibrating parallel to said surface.

In the drawing, element Il represents arelatively large, fiat sheet ofvany suitable material such as cardboard which may be provided with arefi ting surface. Element i2 represents a fin mem r of any suitable,stiff material', for example, cardboard of the type used' in element Il.Fin I2 is preferably positioned to divide the surface of element 'ilinto two substantially equal portions, and means are provided forholding said nn ln'its upright position. Simple means 'for this purposecomprise' tabs' -li cutout and bent 'up duces the sensation of glarewhen element iii is viewed from a position approximately oppositev lamp2l.

Referring", to Eig. 2, beam 4I, lwhich passesthrough polarizer 25, ispolarized to vibrate in a p lane. perpendicular to the surface ofelement il,

as is indicated by arrow 42, the component vi`- brating parallel to thesurface of element il'being removed by absorption within said polarizer.z

When said beam is incident upon the surface of element 'i0 and isreflectedl therefrom, it is substantially depolarized as is indicated byarrows 44. `However, inasmuch as said beam contains no horizontallyvibrating component, there is'no from element il provided with slots I4and adapt- 66 tendency for it to be specularly reflected from thesurface of `element I0, evenwhen incident thereon at the polarizingangle. It follows therefore, that la person viewing said device from.the same position as described above in connection `with Fig. 1 willreceive no sensation of glare..

In utilizing the `display device of the invention, it is desirable toprovide ,on the surface of ele' ment I suitable, relatively highreflecting areas such, for example, as photographs or written matterprinted with relatively shiny ink. i Such areas are indicated at 45. Anobserver positioned in front of said .device will therefore be able to[l0l 2. A display device comprising, in-combination,

see simultaneously similar surfaces villuminatedA by unpolarized andvertically polarized light. Under such conditions, unpolarized lightJacting as described in4 connection with Fig. 1 will cause the said areasilluminated thereby to glare, and any writing or image therein will beindistinguishable. At the same time, the vertically :polarized lightwill illuminate the other half of the surface of element I9 withoutglare, and writing or images therein will be-readily seen or read.

,should also be pointed out that it is possible,

withi'nlthe scope of the invention, to insert in aperture 28 filteringmeans which will assist in ,demonstrating the contrast between a surface"illuminated bylight polarized to .vibrate in a It must be understoodthat the device is effec-f ltively operative only when it is viewed froma plane perpendicular thereto and a surface illu-` minated -by lighthaving different 'polarization characteristics. For example, there maybe inserted in aperture'28 a sheet cf light-absorbing material of suchabsorption characteristicsas to. reduce the intensity of beam 35 to anintensity substantially equal'to that of polarized beam I0. As anotherexample, there may be )inserted in aperture 28 a polarizing filteradapted to impart to beam 35 polarization characteristics different fromthose of 'polarizedbeam 40. It is to be understood, therefore, thatwhenever beam 25 is describedherein and in the claims 'K as havingdifferent polarization characteristics from beam light or any otherstate of polarization for beam x, Since certain changes may be made inthe above construction and different embodiments of the invention couldbe made without departing from/fthe scope thereof, it is intended thatall '.matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not inalimiting sense.-

j I It is also to be understood that the following' y claims areintended to cover all the generic'and v specific features of theinvention herein described,

. i, f projecting Va beam of light obliquely on to said surface, meansfor dividing said surface into a plurality of separate areas, said meansserving also to separate said beam into aplurality of beams, and meansfor polarizing one of said beams to vibrate in a plane perpendiculartosaid surface, the other of said beams having different polarizationcharacteristics from said polarized beam.

means providing a reecting surface, means for projecting a beam of.light obliquely on to said w surface at approximately the polarizingAangle ofl incidence, means for dividing said beam into a plurality ofbeams, means for distinguishing the` area of said `surface whereon oneof said beams is incident from the corresponding Yarea whereon the otherof said .beams is. incident, and means v,for polarizing one of `saidbeams to vibrate in a' 20 plane perpendicular to said surface, the otherof said beams having different polarization characteristics from saidpolarized beam.

3. A display device comprising, in combination, means providing areflecting surface,- means for projecting a beam of light'obliquely ontosaid surface at approximately the 'polarizing angle of incidence, meanscomprising a n element mounted on said surface and vpositioned to dividefthe'area' thereof' illuminated by said beam into a plurality ofseparate areas, said n element b'eing adapted to separate said beam intoa plurality of beams, and means for polarizing one of said beams tovibrate` in a plane perpendicularto said surface, the "other of saidbeams having diierent polarization characteristics from said polarizedbeam.

4. A display device comprising, in combination,

means providing a substantially flat vreflecting surface, meansfor,proj'ecting a beam of light i0 obliquely 'on to said surface atapproximately the '40, said phrase is intended to cover unp'olarized f35 than that wherein the horizontally vibrating component is removed. y

and all statements of the lscope-of the invention which, as a matteroflanguage, might be said to fall therebetween.-

Havingdescribed my invention, what I claim as new and desire to secureby Letters Patent is:

1. A display device comprising, in combination,

means'providing a refiectingfsurface, means'for polarizing angle ofincidence, means comprising a fin element mounted on said surface andpositioned to divide the area thereof illuminated by V,said beam into aplurality of separate areas, said fin element being adapted torseparatesaid beam -into a plurality of beams, vmeans comprising alight-polarizing element interposed in the path of one of said beams,and means for positioning said polarizing element with its transmissionaxis b0- substantially parallel tothe plane of incidence of said beam onsaid surface.

v5. A display device comprising, in combination,` means providing -asubstantially flat reflecting surface, means 'for projecting a beam oflightV obliquely onto said surface at approximately the polarizing angleof incidnce, means comprising a. fin element positioned to divide theareaof said.

.surface illuminated `by` s'aid beam into a plurality of separate areas,means for holding said 00 fin.v element in a position parallelto thedirection` of propagation of said beam and perpendicular to saidsurface, said iin element being of suilcient height to separate thatportion of said beam incident on one of said separate areas from the a5portion incident on the other said.separate area,

and means Afor polarizing that portion. of said beam incident on one ofsaid areas to vibrate in a plane perpendicular tosaid surface, the otherportion cf said beam'- having different polariza- 10 tioncharacteristics from s'aid polarized beam.

, t vRICHARD T. KRIEBEL.

